Rob Kurzban
Subject: Can Evolution Explain Our Feelings?
Bio: Author of All the Feels: The Evolved Function of Every Human Emotion and Sensation
Transcript:
Larry Bernstein:
Welcome to What Happens Next. My name is Larry Bernstein. What Happens Next is a podcast that covers economics, politics, and culture. This episode is Can Evolution Explain Our Feelings?
Our speaker is Rob Kurzban who is the author of a new book entitled All the Feels: The Evolved Function of Every Human Emotion and Sensation.
I want to learn from Rob about how our basic sensations like hunger, pain, and sense of awe can be explained by Darwin’s Theory of Evolution.
Rob, can you please begin with six minutes of opening remarks.
Rob Kurzban:
I want to start with a little story about my sister’s pet iguana named Iggy. When my sister was eight, she asked how Iggy knew what to do. I knew that Iggy had a brain that was evolved, that led to his behavior, but how did he decide when to sit on his hot rock, when to munch the lettuce, when to take a nap? Many years later, it’s possible to sketch the right answer. Evolution led to brains. These brains give rise to feelings that motivate us in different ways. The key point is that feelings are useful, they tell iguanas and people what they need to do.
As much as pain hurts, it’s still very useful. A life without pain would be fatal. People who can’t feel pain die young because they bite their tongues and don’t notice broken bones. Pain feels bad for a reason, it’s measuring damage to your body. Every feeling you’ve got has a job. Hunger, envy, awe, the urge to yawn, all of them are for something. I start with the same place with everything, which is Darwin’s theory of evolution by natural selection. The central issue is function. What is the feeling for? For something to do its job, the feeling has to measure something inside or outside the body. Is there food in my stomach? Is there danger nearby? Is there a mate to impress? And then what is it motivating you to do?
With hunger, its function is to keep you fueled. It measures your caloric needs, how long has it been since you ate, how much glucose is in your blood, and if that measurement is low, it motivates you to go find food. Psychology sorted emotions using their intuitions, positive emotions versus negative, aimed at the self, versus others. I use the evolutionary view, which points to function as the way to organize things. I built a taxonomy with five kingdoms of feelings. The first one is body maintenance: hunger, thirst, the need to breathe, and then all the little departments to take out the solid, liquid and gaseous trash.
The second kingdom is external dangers and opportunities, fear and disgust on the one side, and then on the other, pleasures, a good meal, sexual activity.
The third kingdom is the social world, all of the social feelings that have to do with navigating the world with other people: love, grief, gratitude, anger, envy, shame. This is the biggest one because humans are very social.
The fourth one is the mind, thinking, curiosity, confusion, frustration, and awe.
I have a fifth kingdom, which is my escape hatch, Deja vu, that weird feeling of pain when someone makes a bad pun, that weird urge you have to squeeze something cute.
Let’s take envy. Envy makes the list of seven deadly sins and the ten commandments, thou shalt not covet. What envy does is it measures how well someone around you is doing better than you, and it motivates you to try to get whatever they’ve got: the good job, the better car, the better mate. Envy is well engineered; it doesn’t just make you envious of anybody. People aren’t envious of Elon Musk. People are envious of the people who are around them, the people that have things that they might plausibly get. This is a good way to see that natural selection is at work, it’s well engineered to measure and motivate something that is plausibly going to lead to better outcomes for the individual.
You have a lot of different feelings, and the key piece is to understand that they have a job to do. Over the course of evolution, the function had to do with motivating you to do something that was going to be good for your reproductive success or your survival. So, what I encourage you to do. Next time you experience a feeling, ask what is it measuring? What is it trying to get you to do? Think about that answer, and then make a decision about acting on it.
Larry Bernstein:
You’ve organized each chapter of the book around a specific human feeling or function. Why did you build your arguments around Greek mythology?
Rob Kurzban:
A couple of years ago, I was traveling with Angie, my partner, in Greece, and that was when I decided to spend two years writing the book. It’s an homage to that trip. As we were going through Greece, I was reminded of these myths and how skillfully the ancients captured so much about human psychology, human dynamics, and human emotions. There’s something very true about how artists have captured human psychology that goes beyond what academic psychology has done. The ancients, and then the playwrights, Shakespeare, maybe Christopher Nolan, understand and explain people in a way that goes beyond what we have in scholarly research. For me it was seeing this vast panoply of emotions explored in the classics, in the plays, in the stories, that inspired me to think about many of these individual feelings.
Larry Bernstein:
Can you give an example of a chapter that incorporates a Greek myth?
Rob Kurzban:
One myth that stood out to me was the beginning of the Trojan War. When the gods were celebrating a particular wedding, this was going to be the two people who would go on to produce Achilles, they left out Eris, the goddess of discord. She has this apple that she rolls in, and the apple has to go to the fairest. There’s a contest to see who’s the fairest of them all, and the three goddesses involved, Hera, Athena, and Aphrodite, say, if you name me, I’m going to give you this reward. Paris chose Aphrodite. Aphrodite said, I’m going to give you Helen of Sparta. The reason that she did that was because she was resentful of not being included. Here you’ve got this emotion resentment, which measures, did I get the thing I was entitled to? If you were up for a promotion and the boss’s friend got it and you didn’t, you would feel resentment. That’s measuring the distance between what you were entitled to and what you actually got. I like this myth because resentment isn’t something we talk about a great deal, and yet it started the whole Trojan War that started the decline of the Bronze Age. This emotion could have this spin-off effect, and the myth helps you get into the head of this goddess who’s feeling this feeling so much that it motivates her to cause this chaos.
Larry Bernstein:
Every chapter, whether it’s an emotion or a physical trait, gets explained by Darwin’s theory of evolution. Why make evolution the organizing principle for every single piece of who we are?
Rob Kurzban:
My background is as an evolutionary psychologist, and one of the core principles of that is that whenever you see something in nature that is complex functional design, we have one explanation for where that can come from, which is evolution. People say, “what about culture?” For me, culture is the effect, not the cause. Culture is something that brains produce, and brains are produced by evolution by natural selection. It’s not that evolution is my first choice, it’s that it’s the only game in town. It’s the only scientific explanation we have for why you see organized functional parts of matter, everything from amoebas to cats to human brains. Everything that’s complicated and has a job has an evolutionary explanation, and the trick is to figure out what the right one is. That’s why I lean heavily on the scholarly literature, because you can’t just make stuff up. You have to see the evidence.
Larry Bernstein:
Paul Rozin spoke on the podcast a couple of months ago discussing disgust and meat, Why some people love meat and others hate it, and the taboos wrapped around it. Use disgust and food as a case study in how evolution effects behavior.
Rob Kurzban:
Disgust is a great one, my former colleague Paul Rozin has done excellent work on this. You need this emotion to identify dangerous stuff that have pathogens related to decaying flesh. Meat is a rich source of nutrients, but a dead animal has no immune system and it can’t shew away pathogens that can prosper on meat. Humans need disgust to keep them away from something that is contaminated with pathogens and toxins.
Sexual disgust, people think it’s disgusting to having sex with people who are closely related to them, because of the genetics of inbreeding. The disgust is the system that measures physical dangers of contagion but also social danger. There’s something puzzling about many human cultures have taboos preventing people from doing something they don’t want to do anyway.
Most humans don’t want to have sex with a close relative, and yet there’s this big prohibition on it. Why are we preventing people from doing stuff they don’t want to do in the first place? That’s a mystery.
Larry Bernstein:
For most of human history the danger was starvation, not overeating, so our hunger system evolved to encourage us to eat more food whenever we found it. Now it has flipped. We eat too much, life expectancy suffers, and drug companies are racing to fix a problem evolution never anticipated. Explain how measurement and hunger work in the body.
Rob Kurzban:
It’s complicated. You might think hunger’s pretty easy, is my stomach full, and if it is not full, then feel hungry. It’s not like that. There’s this whole symphony of hormones and measurements, there’s neurons that are responsible for measuring how distended your stomach is, which is basically telling you how full it is. And there’s systems in your brain that are getting information about how much sugar is in your blood. Your brain has to integrate all of these into some sense of how hungry you are. Mostly the problem that our ancestors face, like every organism on the planet is having not enough, you’ve got to motivate the organism to seek out food when it can get it. You get these sweet things and then you taste them and I want to eat more of those; that’s evolution’s way of saying you’ve got a good calorie package that you should exploit.
I love capitalism, but one consequence of a capitalist economy is that a food company wants to figure out how to short circuit your head that says, I’m full, I don’t need to eat anymore. I want to undermine that so that you eat more of my thing, and those companies that do that well are going to win.
We’ve got old measurement systems fighting a modern marketing system, which is designed to find foods and flavors and combinations that undermine the satiety system that says, you’ve eaten enough. If you ask people who are on GLP1s, a lot of them say, I just don’t feel motivated, not that I don’t feel the hunger. Contrast that with other solutions to feeling hunger, if you staple the stomach, people feel hungry and they just know that if they eat, they’re going to feel unpleasant.
That is a pull instead of a push. That’s a good way to think about the differences in these interventions.
Larry Bernstein:
My bird feeders give me a natural history lesson each day. The peanut feeder causes total pandemonium because it’s such a rich, high-fat resource. But the birds only show up early in the morning and vanish by late afternoon. My bird feeder specialist told me that I needed to place the feeders near trees so the birds can hide and not feel exposed to hawks. What does that tell us about how birds weigh the value of a food source against the risk of predators, and what does that show us about our own similar trade-offs?
Rob Kurzban:
I also stock bird feeders at the back of my house. That’s the myth about where Darwin started, if you look at the shape of bird’s beaks, that tells you something about what diets they’re choosing. The birds that have the beaks that are best at getting the food that they can best consume are going to out-reproduce the other ones. Pandas are an example where there’s just one food that they’re specialized for harvesting. If you measure that there’s something out there that has a lot of calories, and I can get a big calorie package in a relatively short period of time, which minimizes my exposure to predators, I’m super motivated to eat that.
I like your point about the birds, because what that speaks to is how different feelings are competing with each other for control of the body. You have a fear system designed to measure the probability that I’m going to get preyed on, hawks hunt at dusk and dawn, so your fear system is don’t go eat, and your hunger system is like, you’re pretty hungry, you should go eat. The resulting behavior is the output of whatever that competition results in, if the animal’s starving, it’s worth the risk, but if it’s not starving, the fear system is going to be like, stay home. Thinking about feelings this way, it’s all a competition. This is my experience of the world, I have these conflicting feelings, like I want to go work out, but I’m hungry and I don’t really look forward to the pain, but I know I will look forward to feeling better. We have these conflicting feelings in our head, but at the end of the day you have to choose one. That’s what is super interesting about thinking about feelings in this way.
Larry Bernstein:
Take air composition, the most basic measurement your body requires. Why is our air system so good at measuring CO2 and so bad at measuring other dangerous gases?
Rob Kurzban:
The anecdote which caught my attention was where some NASA engineers walked intentionally into a chamber which had been filled with nitrogen. You might have thought that when you walk into a chamber with no oxygen, you sense it and exit. That is not what happens, they simply passed out, unaware that they were getting not enough oxygen. The main system in our body to detect whether we’re getting oxygen is a system to detect carbon dioxide in the blood. Normally oxygen and carbon dioxide are completely inversely correlated, because your cells engage in respiration, they use up the oxygen, carbon dioxide comes out. But in this case, the system wasn’t designed to work when there’s no new oxygen coming in. It’s easy to detect carbon dioxide dissolved in the blood, because of the way pH works. This system is designed to detect carbon dioxide in the blood, if you’re underwater and holding your breath, your carbon dioxide will go up and your oxygen won’t go up, because you’re just holding your breath, and normally that works just fine. As an evolutionary matter, measuring how much CO2 is in the blood does perfectly fine to motivate you to breathe when necessary. But in this particular instance, because you’re not measuring oxygen as it’s declining, you wind up where you’re not motivated to escape the environment. That’s how evolution works, it takes whatever it can measure to do the job, gets it done, and then the modern environment comes along and gives us a super crazy context, and then it doesn’t do the job properly. This is no different from what we were talking about in the context of hunger, we’re just in this world where tempting treats are around us.
Larry Bernstein:
In 2020, I had a bad case of COVID. My oxygen levels dropped into the 80s and I was hospitalized. Dr. Ari Ciment, who’s been on this podcast multiple times, was my doctor and he laid out my medical plan: plenty of steroids and 30x the normal concentration of oxygen pumped straight into my nose. If that didn’t work, then he would place a plastic bag over my head to maximize oxygen intake. I knew that bag would send me into a panic. He said the fear would pass in seconds, once I took that first breath and realized I was okay, then my emotional system would relax.
That sounds like two separate measurement systems firing at once, a fear system reacting to the terrifying idea of a bag over your head, and a second system tracking whether I was building up too much CO2, which I wasn’t. How does the CO2 measurement system override the fear of asphyxiation?
Rob Kurzban:
That’s a really interesting example. I have claustrophobia, and the process for me is not that different from what you described, if I’m in a window seat of an airplane, I do some CBT self-talk and I say, nothing’s happening to me, I’m going to be fine. A million people do this every second.
You get these higher-level things, the central processor, which in your case was getting this information, I’m fine, this is going to be okay. But it doesn’t stop the other system from doing its thing. It still takes a minute. These evolved systems are pretty robust, in the case of claustrophobia, my fear system is set to a very high level, if you put a plastic bag over my head, I can’t even think about it, and you’re going to have that experience of unpleasantness, and then it’s just a question of what can you do to balance it out. That’s a super interesting feature of our systems, you can balance them out, but that doesn’t necessarily mean that you’re not still experiencing it.
If you’re on the road and someone cuts you off, you know that there’s no point in taking revenge on that person. The anger doesn’t just go away because it’s irrational. Those systems are in there are deep. You can inhibit them to some extent, but they need time to finish doing their work, and then you get the relief from it.
Larry Bernstein:
I read your prior two books. There’s an intellectual arc across all three. Explain how each one builds on the last, and how you got from where you started to where you are now.
Rob Kurzban:
I was very lucky to work with John Tooby and Leda Cosmides at the University of California, Santa Barbara for my graduate work. My purpose was to explore how the theory of evolution by natural selection could help explain and understand human experience and human behavior. The first book I wrote, Why Everyone Else Is a Hypocrite, was to bring ideas about evolution to a wider audience. One of the main points is that this approach allows you to think about the human mind as having lots of different pieces, each of which has a specialized job. There’s no person inside the person, there’s no little mind inside the big mind, we’re all just a lot of different parts trying to make our way through the world.
The second book was about politics; it takes off where the first one ends. It was called The Hidden Agenda of the Political Mind, the idea there was people adopt positions with respect to policy and they give you a good-sounding explanation for why they adopt that view, but that’s often not the real reason, there’s a hidden motive in the reason that people adopt their views. This is on all sides of the political aisle, everyone says I’m in favor of this because it’s a policy that will benefit the world, and if you dig into it, it benefits them and people like them, now, not 100%, but that’s the way to bet. How we deceive ourselves, or lie to others, about our political views, and how the modular mind explored in the first book explain that.
This third book takes up a second thread, if the evolutionary point of view explains policy, it can explain hypocrisy, it can explain self-deception, but can it explain everything we feel? That’s the culmination, it doesn’t just get policy, it doesn’t just get hypocrisy, it gets everything we can experience as humans. It’s why do you have the feelings that you have from hunger to awe to confusion. My view is that the scholarship for understanding human social behavior is very poor, I say that as someone who participated in it. A big part of the reason that it’s as bad is because not enough people have adopted the evolutionary point of view to understand and explain human behavior.
Larry Bernstein:
I end each podcast on a note of optimism. Why are you optimistic about a growing understanding for measuring what we feel?
Rob Kurzban:
I am optimistic that the field is changing. There is more and more attention being paid to the fact that psychology has failings. People talk about the replication crisis, the idea that studies in psychology have not replicated, and people are starting to take that much more seriously. That is going to improve the standards in the field, the methods that are used, the statistical techniques, and provide the guardrails against AI contaminating scholarship in a negative way.
When I started in my field, using evolutionary psychology was taboo. And now it’s one of the main tools that people use. Science is slow, it takes a long time for good ideas to spread, but good ideas, good methods, good statistics, rigorous analysis, and a theory that withstood the test of time, that’s starting to catch on, albeit slowly.
Larry Bernstein;
Thanks to Rob for joining us.
If you missed our previous podcast, it was is I Love Your Accent.
Our speaker was Valerie Fridland, a Professor of Linguistics at the University of Nevada at Reno. She is the author of the new book entitled Why We Talk Funny: The Real Story Behind Our Accents.
Valerie explained why accents developed and the reason for their differences. I grew up in Chicago and I don’t think I have an accent, yet she explained why the Chicago accent is the most difficult to understand. How is that possible?
Previous episodes and transcripts are available on our website as well as at Apple Podcasts and Spotify.
I am Larry Bernstein with the podcast What Happens Next.
Check out our previous episode, I Love Your Accent, here.
